Continuously variable transmission

ABSTRACT

New equipment for continuously variable transmission, essentially composed by a disc with variable inclination (I), articulated by means of automatic servo-mechanism (C), positioned in the driver axis (A); the inclined disc system activates an oscillatory ring, also called pivot (D), by means of two opposed bearings (B) fixed in the pivot; the pivot activates two alternative elements of opposed power transmission, called rod (E); the force transmitted by the rods is applied to an arm of opposing levers, called balancer (F), with a turn radius originating in the center line of a transversal axis (M) positioned in the center of the transmission; in one side the transversal axis is installed in the interior of a semi-axis (P) and transmits continuous rotation in only one direction by means of a sprag bearing and on the other side symmetrically; in the internal side of the set, there are external conical helical gears (K), integral to the semi-axis; the exit-axis, or moved (H), is the own axis of a sprocket (G), positioned symmetrically between both gears, which center line is axial to the entrance axis of the transmission, being able to have a lateral exit of 90° or inclined exit in relation to the entrance axis; the sprocket receives the torque from one of the gears when the driver axis turns.

The object of the present patent, is a detailed description attached with illustrative figures, of a new equipment of continuously variable transmission (CVT), possessing several marketable applications, fulfilling an existing gap in the demand of continuously variable automatic transmission with a torque superior to 150 Nm, and also for torques below 150 Nm. This product is the result of improvements in old concepts and the creation of new theoretical concepts to meet the technological solutions of this gap, regarding technical characteristics as well as for low investments, obtaining a main product and related products of the new created concepts. The penetration of the resulting products has market application possibilities: general industry, agricultural machines, off road vehicles, naval industry, automotive industry, in eolic energy generators and in hydrokinetic energy generators, in the last two cases the CVT works as a mechanical regulator of angular velocity (rpm), associated with a multiplying box installed between the turbine (eolic or hydrokinetic) and the power generator.

CVT is the English abbreviation for Continuously Variable Transmission. The CVTs are classified in three large groups according to its functionality principle, being: friction transmission, free-wheel (coming and going or oscillatory) and hydrostatic.

-   -   The friction transmissions are the toroidal and of variable         pulley and have at least two rotating bodies, having one contact         point among them, with the same tangential velocity, where the         transmission ration varies changing the effective contact radium         of both elements. Some classical examples of friction         transmission are: the Van Doorne metallic belt, the chained Van         Doorne, the toroidal shift, Torotrak transmission, the Extroid         transmission, the Milner transmission and the ringed-cone         transmission, all of them generally small-sized used in         automotive vehicles, machinery, small-sized and low torque         equipments.     -   The free-wheel transmissions, or coming and going or         oscillatory, are transmissions in which the rotation in the         entrance axis provided a determined mechanism, converts into an         oscillatory movement of variable amplitude, in which this         movement of coming and going is rectified with a free Wheel in         order to obtain a unidirectional rotation movement in the exit         axis. Using several mechanisms in parallel it is possible to         transmit continuously and minimize undulation of the exit angle         and thus minimizing the torque oscillation in the exit axis.         These transmissions are not commonly used in the automotive         industry due to the difficulty of configuration and exit speed         inconsistency and subsequent vibration due to the intermittent         torque transmission. Some classic examples of free-wheel         transmission are: the Lestraneng transmission, the Varibox         transmission, the continuously variable IVPD transmission, the         Constantinesca transmission, and the Transrevolution         transmission.     -   The hydrostatic transmissions are the ones that transform         rotational energy of an entrance axis in fluid flow in a pump         and later this fluid flow is converted in a rotating movement of         an exit axis by means of a hydrostatic engine or turbine. In         these transmissions, sometimes the flow is varied through the         variable output pump and in other times the output is controlled         by control valves and thus the transmission relation of the         system, obtaining an infinite array of velocities. This type of         transmission has the advantages of having big configurations,         they are usually used in utility mechanisms, tractors and heavy         vehicles, but they are not applied to high rotations. Some         classic examples of hydrostatic transmissions are that apply a         variable pump with axial pistons activated by an inclined disc         with variable angular inclination.

There are some documents that describe continuously variable transmissions destined for several applications, although none of these transmissions has the configuration, application and functions described in this patent. Among these documents it is worth mentioning the following:

THE BRPI 0315187-5, CONTINUOUSLY VARIABLE TRANSMISSION, Which describes a continuously variable transmission for use with engine run vehicles. An electronic control unit is included, an automatic gear shift unit, an inverter, a set of entrance gears, an element of fixed entrance relation and an element of fixed exit. The electronic control unit is configured to include the rules of logic to control the transmission; the rules of logic include emitting control commands of the transmission.

THE BRPI 0407856-0, CONTINUOUSLY VARIABLE TRANSMISSION, This patent describes the invention of a variable velocity transmission that has a plurality of inclination spheres (1) and entrance discs (34) and exits (101) opposed, being illustrated and described, which provides an infinite number of velocity combinations per its relation of transmission. The use of a set of planetary gears enables that the minimum velocities are in the inversion and the unique geometry of the transmission allows that all of the power courses are coaxial, this way, reducing the general size and the complexity of the transmission, in comparison to transmissions that reach ranges of relations in similar transmissions;

THE BRPI 9301842-8, OUTPUT VARIATION DEVICE IN ROTATING PUMPS OF POSITIVE OR VARYING DISPLACEMENT OF ROTATION SPEED IN HYDRAULIC AND PNEUMATIC ENGINES, AND HYDROSTATIC VARIATION OF ROTATION SPEED, is constituted of all and any mechanical element or set of elements that has the property of varying the useful width “I” (3), of internal and external gears, lobos, lobos with tooth, friction wheels, cubes, picks, bolts, etc., that comprise a rotating pump and or hydraulic rotating engine and/or pneumatic, with the junction of the variation device of the output in rotating pumps and the device of rotation variation in hydraulic rotating engines and pneumatic, forming the hydrostatic variation of rotation speed; and

THE BRPI 9604066-1, GEARS PUMP WITH VARIABLE OUTPUT BY THE AXIAL DISPLACEMENT PRINCIPLE OF THE MOVED, REVERSIBLE GEARS IN HYDRAULIC ENGINE, this invention provided the pumping of fluids at a variable output without the need to vary the rotation speed of the starter and without the need to obstruct the consolidation output and the recirculation of the exceeding output to the suction pump, saving fuel and rationalizing the controls of the hydraulic circuits. This principle consist in varying the positions of gears (“useful width”.) between the external teeth driver gears (4) e moved (9), varying the volume pumped at each revolution. The driver gear (4) does not have longitudinal movement. When they are not geared, the opposite extremities from each other of the gears has empty spaces between the teeth, occupied by the internally teethed gears (3) and (10), preventing the internal recirculation of the fluid. The increase of the useful width is obtained by means of the internal hydrostatic forces; the decrease is obtained by the movement of the axis (8) and the journal bearing (2), cooperating between them that dislocate axially for left to right taking the internal teeth gears (3) and the moved gear (9) in the same direction. The internal teeth gear (10) does not move in the axial direction. The triggering of the mobile parts in the axial direction is obtained by means of hydraulic command using its own pumped fluid, recirculation it until the command mouth (15), or obtained by means of external mechanisms. The gear pump of variable output is reversible, with the possibility of being used as a hydraulic engine of variable rotation speed. In this case there a constant output of fluid destined to transmit power to the axis of the mentioned hydraulic engine, being that the axis has its variable rotation speed due to the internal useful width of the engine, obtained by the same principle of gear pumps at variable output;

There are some other documents that can be cited of foreign patents like the WO 2006049500, the EP 0478514 or EP 1991 0830381, the U.S. Pat. No. 7,137,798, and the U.S. Pat. No. 7,153,110.

The continuously variable transmission (CVT), object of the present invention patent, has as functional characteristics the use and improvement of two known function principles:

The first, also used in pumps with variable axial pistons in high pressure oil-hydraulic circuit, is the one with conversion of variable or Constant rotating movement, in alternative movement in controlled course in real time, by means of a disc with variable angular inclination, articulated by means of a automatic service-mechanism (FIGS. 1C and 2C), positioned in the driver axis, in which the triggering of the primary machine comes from. The inclined disc system was modified and, instead of triggering the axial pistons, it triggers an oscillatory ring, or pivot (FIG. 4) by means of two opposing bearings fixed in the pivot (FIGS. 1B, 2B and 4B). The pivot triggers both transmission alternative elements of opposite forces, called rod (E).

In this configuration, the improvement results in the creation of two new concepts:

-   -   the application of force in both directions of the movement         (coming and going), with the introduction of the oscillatory         ring, (or pivot) that involves the angular inclined disc, and     -   The introduction of a variable over-width in the point of         contact between the angular inclined disc and the bearings         (dimension “e”—FIGS. 1, 2, 4 e 8) to rectify the exit torque         (FIG. 9).

The second function principle, improved and used in this Project, it is used in free-wheel transmissions, in which the re-conversion takes place, by means of a one-way bearing, or sprag (turnpike) bearing installed in the unidirectional journal bearing of the alternative movement of variable course of the rods, in rotating movement of controlled velocity. The force transmitted by the rods is applied to an arm of opposite lever, called balancer (F), with a rotation radium in the Center line of a transversal axis to the driver axis (M), positioned in the center of the transmission. The balancer transfers the angular oscillatory movement to the transversal axis. The transversal axis turns from zero, when the transmission relation is zero until the required angle by the transmission relation, always inferior to 180° and returns to zero. The turn direction of the transversal axis inverts itself when it reaches the maximum and minimum limits. At every 180° turn from the driver axis corresponds to a transmission cycle of torque to the transversal axis. The amplitude of the cycle is the function of the inclination angle of the disc, α, (FIG. 2) and determines the transmission relation, “i”. One side of the transversal axis is installed in the interior of a semi-axis (P) and transmits a continuous rotation in only one direction, by means of a one-way bearing (sprag bearing) (L). On the other side, symmetrically and same position in the reverse plain, there is another semi-axis, identical and with the same function, but with an opposite rotation direction, obtained by the inverted assembly of the sprag bearing (L). In the extremity of each semi-axis, in the internal side of the set, there are an external conical helical gears (K), integral to the semi-axis. The exit axis, or moved (H), is the own axis of a sprocket (G), symmetrically positioned between both gears, which center line is shown in the figures as being axial to the entrance axis of the transmission, but can have a lateral exit at 90° or inclined with relation to the entrance axis. The sprocket receives the torque from one of the gears when the driver axis turns in the first and second quadrants and the other gear, when the driver axis turns in the third and fourth quadrants doing it successively. The innovation introduced in this second principle it is characterized by creating two other new concepts:

-   -   The amplitude of the cycle is function of the inclination angle         of the disc and determines the transmission relation, “i” and         the reduction or multiplication of rotation speed is         transfinite, or continuously variable within an interval of         rotations, with only three gears, since each 360° turn of the         motive axis correspond to two application cycles of torque in         the moved axis when i=1.0.     -   The rotation speed of the moved axis (or exit) can start from         zero to the maximum adopted value of each Project, independently         from the rotation speed of the driver axis, dismissing clutch or         hydrodynamic converter of conjugated starter.

Thus, the continuously variable transmission, object of the present patent, describes a movement mechanism, transmission related that reduces exit rotation to zero and multiplies it until 1.3 in the same configuration, not depending on the rotation speed of the entrance axis, destined to several applications, presenting a new and unique configuration providing great advantages in relation to the already existing transmissions used and found at the moment. Among these advantages it is worth mentioning:

-   -   The fact that it is a more versatile product regarding the         market segments, with possibilities of applications in agitators         of a typical vertical cylindrical chemical reactor, where the         use of CVT dismisses the commonly used planetary reducer,         because its transmission relation, “I”, start from zero and         reaches a wide range of rotations;     -   Also the fact that it can be used in eolic generators         (aerial-generators) or hydrokinetic generators for the         conversion of kinetic energy river currents into electric         energy, which a gear box multiplies the rotation of the turbine         axis (eolic or hydrokinetic) that turns in low rotation and in         unstable velocity due to the instability in flow velocity;     -   Still in the application for high torque automotive mechanical         transmission, for the fact that it starts from zero, dismisses         the use of a clutch or conjugated hydrodynamic converter,         decreasing manufacturing and maintenance costs.     -   The possibility of using it in other segments of the industrial         market, such as mining, cement industry, management of         materials, harbor installations, water treatments, plastic,         rubber, paper and cellulose, paint, food, beverage, tobacco         industries, agro-industry in general, etc.; and     -   Still the concept of an inclined disc can also be applied, that         would transmit to the rods an alternate movement with controlled         extension in real time, to benefit indirectly other products, as         in the case of the market of modern air compressors and cooling         gas that, for energy saving, currently control rotation through         the frequency inversions of the electric engine, with the         objective of balancing the demand and quantity of generated         work, avoiding peaks of starter chain of the electric engine. In         this case the rods activate directly the pistons of the         alternative compressor, dismissing the use of unidirectional         bearings of the sprag bearing.

Next there are references to Figures that are attached to this descriptive report, for better understanding and illustration, in which:

FIG. 1: shows part of the configuration of the continuously variable transmission, object of the present patent, focusing on the inclined disc and the balancer, seen in a longitudinal cut, positioned at 90 degrees (α=0.0) in relation to the driver axis, or entrance axis, when the angular speed at the exit is equal to zero, independently from the angular velocity in the entrance. It is also highlighted the moved axis, rods and sprocket.

FIG. 2: shows the configuration of the continuously variable transmission, object of the present patent, focusing on the inclined disc and the balancer, seen in a longitudinal cut, at an angle of α=28.3° in relation to the perpendicular axis to the driver axis, or entrance axis, when the transmission relation is equal to 1.3, where the maximum angular velocity in the exit is equal to 1.3 times the angular velocity at the entrance. Highlighting as well, the moved axis, rods and sprocket.

FIG. 3 shows part of the configuration of the continuously variable transmission, object of the present patent, focusing on the transversal axis, the left and right conic gears, each one integral to a semi-axis, the balancer in the center and the left and right one-way bearings lodged in each semi-axis.

FIG. 4 shows part of the configuration of the continuously variable transmission, object of the present patent, highlighting the pivot (D) with an inclined disc (I) in the center and two bearings (B) that transfer oscillatory movement of the inclined disc to the pivot and from the pivot to the rods.

FIG. 5 shows part of the configuration of the continuously variable transmission, object of the present patent, highlighting the balancer (F) and the transversal axis (M).

FIG. 6 shows part of the configuration of the continuously variable transmission, object of the present patent, highlighting the detail n°. 1 indicated on FIG. 3, which shows the assembly of the one-way bearing (sprag bearing) (L) between two sphere radial bearings, hence constituting two opposing journal bearings that transfer the unidirectional movement of the transversal axis to each semi-axis, this integral to the conical gear being that both unidirectional bearings posses an inverted rotation direction, making both conical gears with an inverted rotation direction, transfer the continuous rotation movement to the sprocket (G), and this to the moved axis (exit axis) (H).

FIG. 7 shows in a schematic, a view of the longitudinal cut that represent the transversal axis, both unidirectional bearings, the balancer, both conical gears, the sprocket and the moved axis (or exit), object of the present patent.

FIG. 8 shows part of the configuration of the continuous variable transmission, object of the present patent, highlighting the driver axis, inclined disc, the pivot, the rods and the pistons (S) when these components are applied in the Project and fabrication of products also benefited by the conceptual improvement, as in the case of air compressors and cooling gas, in which seeking energy savings, the quantity of generated mechanical work is balanced with the demand by means of the disc inclination which is commanded by sensors that measure this demand in real time. This configuration enables the substitution of the onerous frequency inversions of the electrical engine, also avoiding the peaks of starter chain of the electrical engine. In this case the rods directly activate the pistons of the alternative compressor, dismissing the use of the unidirectional bearings (sprag bearing), being that the return of the pistons occurs due to the application of the rods' force in both directions, instead of what happens with pumps of axial pistons of inclined disc, which need an external fluid pressurization system nest to the suction, to obtain this return.

FIG. 9 shows the chart that represents the angular position of the driver axis and moved from the continuously variable transmission, object of the present patent, when the transmission relation is equal to 1.0 (number of turns of the driver axis is equal to the number of turns of the moved axis) and the behavior of the angular position in the interval of a complete turn, between zero and 360°, during the movement transmission between them. By analogy, the same chart represents the torque transference behavior between the driver axis and moved axis. The designed curve shows the behavior of the transmission relation when the bearing surface of the inclined disc is plain, no ramp and the consequent torque oscillation. The full line represents the ideal condition, when the ramp is introduced in the inclined disc, which width is equal to “e”, shown in FIGS. 1,2 and 4. This width, which is not uniform, varies the function of the angular position of the contact point between the surfaces of the inclined disc (I) and the bearings (B) of the pivot and acts in all of the punctiform contacts of the circumference of the inclined disc, in a sense of compensating the advances or delays in angular velocity, guaranteeing that the angular position of the exit axis follow the same position of the entrance axis during all of the extension of the 360° turn and thus guaranteeing the continuity of the torque, working free from oscillations and vibration.

In the Figures and in the descriptive report the alphanumerical references represent the elements of the continuously variable transmission, object of the present patent, clarifying and enlightening the description, where: A=motive axis; B=bearings; C=servo-mechanism; D=pivot. E=rod; F=balancer; G=sprocket; H=moved axis; I=inclined disc; K=conical gear; L=sprag bearing; M=transversal axis; P=semi-axis; R=gravity center; S=piston; T=External square key; V=Internal square key.

Next a non-restrictive preferential form is described for the realization of the present equipment, object of this patent, in which the configuration and application can vary in the adequate form for each desired model, describing one of the constructive possibilities that lead to the concretization of the described Project and the way it functions.

The continuously variable transmission, object of the present patent, is a mechanism essentially composed of an inclined disc (I), with articulation in its center of gravity (R), with inclination up to 28.3° (α=28.3°), faced with two directly opposed bearings (B) installed in a pivot (D). The bearings receive the oscillatory movement of the inclined disc caused by the rotation of the driver axis (A), and transmit this movement to the pivot, which in its turn transfer the same movement to the rods (E). The force of the oscillatory axial movement by the rods (E) is applied to an arm of opposed levers, called balancer (F), with a turn radius originating in the center line of a transversal axis to the driver axis (M), positioned symmetrically in the center of the transmission. The transversal axis spins from zero to the angle required by the transmission relation, always inferior to 180° and returns to zero. The direction of the spin of the transversal axis is inverted when the maximum and minimum limits are reached. At each 180° spin of the driver axis corresponds to a cycle of torque transmission to the transversal axis, when “α” goes from −28.3° to 28.3°. Thus, the cycle amplitude is the function of the inclination angle of the disc (α) and determines the transmission relation, “i”. One side of the transversal axis is installed in the interior of a semi-axis (P) and transmit to it continuous rotation in only one direction, by means of a one-way bearing (sprag bearing). On the other side, in a symmetrical and rebated position in the reverse plain, there is another semi-axis, identical and with the same function, but with a sense of opposite rotation. In the extremity of each semi-axis, in the internal side of the set, there is an external conical gear integral to the semi-axis (K). The exit axis, or moved (H), is the own axis of a sprocket (G), positioned symmetrically between two gears, which center line is axial to the entrance axis of the transmission. The sprocket receives the torque from one of the gears when the driver axis turns in the first and second quadrants (from zero to 180°) and the other gears, when the entrance axis turns in the second and third quadrants (from 180° to 360°) and thus successively. The disc inclination occurs by the axial movement of a servo-mechanism (C) composed basically by two tacos-generators or pulse generators, being that one measures the angular velocity of the driver axis and the other the angular velocity of the moved axis. The analogical signals, from 4 to 20 mA (or 5 to 10 V), are transmitted to a signal transducer and to a driver that commands a pace engine. This triggers an endless screw sprocket, that triggers two crown simultaneously and these triggers two spherical fuses that move an articulated lever in the indicated locations by the FIGS. 1 (C) and 2 (C). The command of the servo-mechanisms of the disc inclination can be manual, by means of activation of a linear potentiometer or a capacitive ruler, which positions the pace engine, or automatic through PLC that positions the pace engine by comparison and processing of the variables (velocity, torque, electric current frequency, viscosity of reactor fluid, etc.) to be controlled, by means of a control algorithm that establishes in real time the transmission relation to be adjusted, resulting essentially in a manual or automatic continuously variable mechanical transmission, that adjust the exit rotation in real time in function of the entrance rotation. The control grid is programmed in a dedicated processor (PLC), which is an integral part of the continuously variable automatic transmission, object of the present patent, by means of a specific algorithm for each use, thus constituting in the equipment for several applications.

This, by the configuration characteristics, applications and functioning above described, it can be clearly noticed the CONTINUOUSLY VARIABLE TRANSMISSION is a new equipment and it is unique for the State of Technique, in which full of innovation conditions, inventive activity and unseen industrialization, which makes it worthy of the Patent of Invention Privilege. 

1- CONTINUOUSLY VARIABLE TRANSMISSION, characterized by being a mechanism essentially composed by a disc with variable inclination (I), articulated by means of automatic servo-mechanism (C), positioned in the driver axis (A), in it center of gravity (R), by means of a transversal pin to the driver axis, being that the main axis comes the rotational activation of the primary machine being a turbine, electrical engine, internal combustion engine or others; where the inclined disc system activates an oscillatory ring, also called pivot (D), by means of two opposed bearings (B) fixed in the pivot; which the pivot activates two alternative elements of opposed power transmission, called rod (E); the force transmitted by the rods is applied to an arm of opposing levers, called balancer (F), with a turn radius originating in the center line of a transversal axis (M) positioned in the center of the transmission; where the balancer transfers the angular oscillatory movement to the transversal axis; where the re-conversion of this alternative movement (comes and goes) in rotating movement of controlled velocity happens with sprag bearings (or one-way) (L) installed between two radial bearings in the unidirectional bearings; where the two unidirectional bearings are constituted by a transversal axis to the driver axis (M); where in one side the transversal axis is installed in the interior of a semi-axis (P) and transmit continuous rotation in only one direction by means of the sprag bearing and on the other side synthetically and on the exact position in the reverse plain, there is another semi-axis, identical and with the same function, but with an opposite rotation direction, obtained by the inverted assembly of the sprag bearing; in the extremity of each semi-axis, in the internal side of the set, there is an external conical helical gears (K), integral to the semi-axis; where the exit axis, or moved (H), is the own axis of a sprocket (G), positioned symmetrically between both gears, which center line is axial to the entrance axis of the transmission, being able to have a lateral exit of 90° or inclined exit in relation to the entrance axis; where the sprocket receives the torque from one of the gears when the driver axis turns in the first and second quadrants and the other gear, when the driver axis turns in the third and fourth quadrants and so on. 2- CONTINUOUSLY VARIABLE TRANSMISSION, according to claim 1, part of the continuously variable transmission, characterized by creating a second concept in which is possible to apply force in both directions of the alternative movements of the rods (E) with the introduction of the oscillatory ring, or pivot (D) that involves the inclined disc, differently from what happens with radial piston pumps activated by an inclined disc, variable or not, where the return of the pistons happens by previous external pressurization of the fluid to be pumped, enabling its use in pumps or in alternative piston compressors, with coming and going of the pistons activated by an engine, in which the pistons are directly activated by rods, without the need of using the unidirectional journal bearings with sprag bearings, installed in the transversal axis. 3- CONTINUOUSLY VARIABLE TRANSMISSION, according to claim 1, part of the continuously variable transmission, characterized by introducing an over-width in the face of the inclined disc, “e”, with variable measurement in the contact point between the inclined disc and the bearings of the pivot, with the purpose of rectifying the exit torque's curve without the need of using several parallel mechanisms to achieve continuous transmission; where at every angular position of the driver axis corresponds to a different width “e”, non-uniform, that varies in function of the angular position of the contact point between the surfaces of the inclined disc and pivot bearings and acts in all of the punctiform contacts of the inclined disc's circumference, in a sense of compensating advances or retreats in angular velocity, guaranteeing that the angular position of the exit axis follows the same position of the entrance axis during the entire extension of the 360° turn and guaranteeing torque continuity for a vibration-free functioning. 4- CONTINUOUSLY VARIABLE TRANSMISSION, according to claim 1, part of the continuously variable transmission, characterized by being transfinite, that is, possessing infinite transmission relations within an interval of rotations, where it reduces of multiplies the rotation velocity with only three gears, being that the rotation velocity of the moved axis starts from zero until the maximum value adopted by each project, independently from the rotation velocity of the driver axis, dismissing clutch or conjugated hydrodynamic starter converser. 